Apparatus for packaging stacked articles

ABSTRACT

Apparatus for and method of packaging stacked articles, as for instance bags, in a shipping container that is formed of a heatshrinkable plastic film heat-sealed at one end and open at the other end, and, preferably provided with gussets therebetween to facilitate the reception thereinto of said stacked articles in a prearranged pattern. The stacked articles while in said shipping container are subjected contemporaneously to controlled pressure to compact said stacks and to sufficient heat to heat-shrink the plastic film thereabout; thereafter while under compaction, cooling of said heat-shrunk film is effected to produce a relatively rigid package and thereby facilitate the handling thereof, as for instance by palletizing said package.

United States Patent [191 Beninger [451 Oct. 7, 1975 APPARATUS FOR PACKAGING STACKED ARTICLES [75] Inventor: Robert L. Beninger, Sheboygan,

[21] Appl. No.: 421,989

[52] U.S. Cl 53/124 A; 53/184; 53/258 [51] Int. Cl. B65B 25/14; B65B 53/02 [58] Field of Search 53/24, 30 S, 124 A, 184 S, 53/258 [56] References Cited UNITED STATES PATENTS 1,759,357 5/1930 Lacey 53/258 2,402,476 6/1946 Weeks 53/24 3,031,809 5/1962 Muskat et al 53/184 S X 3,363,396 l/l968 Lockrow et al.... 53/258 X 3,555,772 l/1971 Kammer 53/124 A 3,662,512 5/1972 Zelnick 53/30 S FOREIGN PATENTS OR APPLICATIONS 1,395,509 3/1965 France 53/124 A Primary Examiner-Travis S. McGehee Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57 ABSTRACT Apparatus for and method of packaging stacked articles, as for instance bags, in a shipping container that is formed of a heat-shrinkable plastic film heat-sealed at one end and open at the other end, and, preferably provided with gussets therebetween to facilitate the reception thereinto of said stacked articles in a prearranged pattern. The stacked articles while in said shipping container are subjected contemporaneously to controlled pressure to compact said stacks and to sufficient heat to heat-shrink the plastic film thereabout; thereafter while under compaction, cooling of said heat-shrunk film is effected to produce a relatively rigid package and thereby facilitate the handling thereof, as for instance by palletizing said package.

16 Claims, 6 Drawing Figures add/flamed --.u I i 17.- i "::ilii 32 45 ,0; m

3 f O 1 a m .fl m S {lit |1| I P 11111111 1| III. HI MH III/ I THIIIIIIIIIUHINIIJ h mm 5 7 9 1 7 f." C 0 US. Patent US. Patent Oct. 7,1975 Sheet 2 of 3 3,910,011

US. Patent 00. 7,1975 Sheet 3 of 3 3,910,011

APPARATUS FOR PACKAGING STACKED ARTICLES SUMMARY OF THE INVENTION This invention relates to apparatus for and a method of packaging stacked similar articles in an outer shipping bag or other container formed of a heat-shrinkable plastic film. In the embodiment described herein the articles to be packaged are grocery bags made of a plastic film. but the bags may be made of paper or other flexible and foldable web material capable of being collapsed and stacked in a compacted superimposed relationship.

In the practice of my invention, the articles to be packaged may suitably be grocery bags, such as those of the quick-opening satchel type and of the so-called SOS type. These bags have closed bottom ends that are folded back over the bodies of the bags, when in a flattened collapsed state, thereby making such bag ends much thicker than the bodies of the bags. By arranging a plurality of said bags in a collated stack, or in stacks, with their closed folded-over bottoms at alternate ends of the stack a substantial uniformity in the thickness of the stacks lengthwise of the bags can be achieved.

As a first step in carrying out my method, a collated stack of bags is built up, preferably by hand but with the assistance of a hinged, wrap-around type of housing embodying my invention. A pusher plate having upper and lower flanges and an apertured web portion connecting said flanges cooperates with said housing when in its wrap-around, or peripherally closed state to relatively move the stack of bags out of said housing, when ready to be packaged, and into a supported position at which the stack is received by and partially enclosed within an open-ended pre-formed shipping container of a heat-shrinkable plastic film.

While peripherally enclosed, the stack is subjected to compression to compact the stack vertically and is also subjected to the application of heat to complete the enclosing of the stack by heat-shrinking the heatshrinkable film thcrearound. Perferably the compacting step is carried out first and the heat-shrinking of the plastic film is effected while the stack is under the compacting force and/or the stack is in its compacted state.

In its pre-formed state, referred to above, the packreceiving shipping container initially is simply a gussetted sleeve of the heatshrinkable plastic film that is of rectangular cross-section; that is preferably, although not necessarily, closed at one end by a heat-sealed closure of the plastic film itself; and that is fully open at the other end for receiving a stack of the bags or other articles to be packaged. The open end of the article receiving sleeve is defined by an integral extension of the sidewallforming plastic film, and during the heatshrinking step this extension is contracted to and around the contiguous end of the packed stack and is caused to shrink against and conform to the surface of said stack end to be in firmly engaging contact there with. In such shrinkage, the contraction of the extension of the side walls causes a contraction of the opening defined by the edges of such contracted side walls and may also cause a thickening of such film edges to provide a strong, thickened edge for manual grasping purposes.

Before releasing the compacting force acting upon the stack being packaged, the stack, or at least its enclosing plastic film, is quickly cooled down, as by the 1 application thereto of a current of air, or other gas, at

an ambient temperature or at a lower than ambient temperature. This causes a rigidifying of the enclosing plastic film to hold the articles in their compacted state, immobilized relative to one another in the same stack. It is therefore an object of this invention to provide a method of and apparatus for packaging stacked articles in a shipping bag formed of a heat-shrunk plastic film that is in closely conforming contact with contiguous surfaces of compacted stacked articles enclosed in said shipping bag so as to substantially immobilize said articles against relative displacement during handling, shipping and storing.

It is a further object of this invention to provide apparatus for packaging a plurality of the same or similar articles that includes a wrap-around type of temporary housing within which collated stacks of articles are arranged and from which pusher plate means serve to advance said stacks for loading into the open ends of pre formed sleeves of a heat-shrinkable film heat-sealed at their other ends, together with means subsequently effective to compact the articles while in partially enclosed stacks and to heat-shrink said heat-shrinkable film into close surface contact with contiguous surfaces of said stacked and by then fully enclosed compacted articles to facilitate handling and shipping thereof.

Other objects, features and advantages of the invention will be readily apparent from the following de scription of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, and with all variations and modifications that may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which the following detailed description of the annexed sheet of drawings by way of preferred example illustrates several embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken partly diagrammatic, partly logitudinal and partly sectional view, illustrating apparatus embodying this invention for carrying out the method of the invention; and showing in dotted lines an advanced position of a housing and pusher plate means forming a part of said apparatus;

FIG. 2 is a sectional view taken substantially along the line II-Il of FIG. 1;

FIG. 3 is an isometric view of said apparatus with the housing in its opened-up position and with a press and heat-shrinking ring in position relative to a loaded ship ping bag to compact and heat-shrink the same;

FIG. 4 is a longitudinal view partly in section and partly broken away illustrating the operation of a compaction press platen and of a heated ring for heatshrinking ends of the shipping bag to close or substantially close said bag ends;

FIG. 5 is an elevational perspective view illustrating somewhat diagrammatically means for effecting the cooling of a loaded shipping container that is still under compaction; and

FIG. 6 is a perspective view of a loaded shipping bag in its final state after having been heat-shrunk.

DETAILED DESCRIPTION The reference numeral 10 indicates generally a stationary hinged peripheral housing for receiving a stack of articles 11, which are here illustrated as satchel type or SOS type bags, preferably made of a plastic film.

Such bags, as illustrated in FIG. 1, are gussetted and when opened up are rectangular in shape and have multi-ply closed ends 12 provided by folded-over end flaps, and have multi-layer open ends 13. As illustrated in FIG. 1, the closed ends 12 are so arranged that a plurality thereof lie at one end 14 of the stack 15, and another plurality of closed ends 16 lie at the other end 17, of said stack. This arrangement, referred to herein as a collated arrangement, can be accomplished by any suitable mechanical means or by hand.

In either case, collated stacks such as the stacks 15, are positioned in the stationary hinged housing to be temporarily supported thereby in generally horizontal planes superimposed upon one another. While the stack is shown in FIG. 1 as suspended mid-height of the housing 10, this showing is merely in the interest of clarity, since the stacks 15 are actually positioned on one or another of a number of horizontal lower stack supporting surfaces, generally indicated by the letters L and L which will now be more specifically described.

As best shown in FIG. 3, the housing 10 includes a lower panel 20 that initially provides a supporting surface L for stacks like the stack 15. Said panel 20 is rigidly joined along a longitudinal edge 21 thereof to a generally vertical panel 22. The panel 22 is hinged, as at 23, by means of a piano-type hinge along the full length of its longitudinal edge to a third panel 24, which, in turn, is rigidly joined along a longitudinally extending edge 25 to a fourth panel 26 maintained at a right angle to the panel 24. Thus, in its opened-up state, the housing 10 has a bottom provided by the panel 20; a side wall formed by the panel 22 at right angles to said lower panel 20; and a pair of rigidly joined panels 24 and 26 swingable into an out-of-the-way position .(FIG. 3) to permit the arrangement of the previously mentioned collated stacks 15 on the supporting surfaces L and L.

Also, as best shown in FIG. 3, one end of the housing 10 when open is defined by the connected end edges 27, 28, 29 and 30 of the panels 20, 22, 24 and 26, respectively. When in that position, the collated stacks 15 are placed on the supporting lower surface L of the housing 10 with the ends 14 of said stacks positioned against a vertical inner surface 31 of a pusher plate indicated generally by the letter P.

Said pusher plate P has a lower inwardly turned, generally horizontal flange 32 and an upper generally hori zontal flange 33 having an inwardly extending portion 34 and an outwardly extending portion 35, the functions of which will be described below in detail. A generally vertical web or plate portion 36 is preferably integrally formed with the flanges 32 and 33 and is so dimensioned as to provide clearance shown at C (FIG. 2) between all four peripheral edges or surfaces of said plate portion 36 and the inwardly facing surfaces of said panels 20, 22, 24 and 26, when the housing 10 is in its peripherally closed state. Such clearance freely permits relative longitudinal movement of the pusher plate P relative to its housing 10. Since the housing 10 is preferably stationary in its position, this means that the pusher plate P is itself movable, and this is illustrated in dotted lines in FIG. 1.

Movement of the pusher plate P is accomplished manually or in any suitable way. As shown in FIG. 1 an air cylinder 40 operated with air or other gas or fluid under compression provides the force for reciprocating movement of the pusher P acing through a piston rod 41 pivotally connected through a pin and bifurcated boss arrangement 42 to the pusher P. Optionally, in order to facilitate movement of the pusher P in the peripherally closed housing 10, the upper surface of the upper flange 33 is provided with a frictionless coating 43 that extends over both the inwardly extending portion 34 and the outwardly extending portion 35. Such a coating 43, which may be a fluorocarbon, tends to prevent grabbing due to friction between the inwardly facing surface 24 of the housing and the outer surface of the pusher flange portion 33 as the two surfaces move relatively to each other.

To reduce friction between the under surface of the lower flange 32 and the surface L, a number of thin, slender fingers 45 of frictionless, or low friction, material, such as spring steel, extend longitudinally from said flange 32 of the pusher P for a substantial distance (FIG. 3). This arrangement prevents limp bags B or B-l from buckling when moved forwardly from their position in the stationary peripherally closed housing 10 into their advanced position on a supporting surface 46 or L ahead of the pusher P as shown in dotted lines in FIG. 3.

To guide the pusher plate P in its reciprocating movement, the plate portion 36 of the pusher plate P is provided with a number of symmetrically arranged apertures 47 (FIGS. 2 and 3), through some of which freely extend guide rods 48 which are rigidly mounted toward their rearward ends in apertures 49 provided in the upstanding flange 50 of an angle iron 51 (FIG. 1 Those of the numerous apertures 47 not serving to receive the guide rods 48 serve to release air that might otherwise become entrapped between the plate portion 36 of the pusher plate P and the adjacent end of the loaded shipping bag shown at B (FIGS. 4 and 6) and shortly to be described herein.

The shipping bag B is a relatively large bag, preferably formed of a heavy, transparent or translucent plastic film that is heat-shrinkable to an extent of up to 40 to 60 percent in biaxial directions. Polyvinyl chloride (PVC) or an oriented polyethylene or other plastic material that is capable of being heat-shrunk to the extent just indicated at temperatures between 300 and 450F is generally satisfactory for forming into a shipping container or bag B such as herein disclosed for receiving the stacks 15 of the superimposed layers of grocery bags previously mentioned herein. It will be understood, however, that any stackable articles that are identical in form, shape and size or are of the same general type and dimensions can be handled in the manner and by the apparatus herein described and illustrated.

Initially, pre-forms B-l of the shipping bags B are provided that are generally tubular, that are gussetted and that are generally rectangular in outline along all four longitudinal sides thereof, with one end 52 open (FIGS. 3 and 4) and with the other end 53 heat-sealed along a seam 54 in a median plane but with some outward bulging of such end 53 as shown in dotted lines in FIG. 4.

From the peripheral housing 10, the stack 15 upon its completion is transferred, as best shown in FIGS. 1 and 3, to the supporting surface 46 or L' above which is a compacting press 60 with its platen 66 and a heated shrink ring 61. Before effecting this transfer, a shipping container pre-form 8-1 is manually slipped over the peripherally closed housing 10, open end 52 first, until the prc-form B-l is in the position shown in FIG. 1 with the stack 15 still within the housing resting partially on the flange 32, the fingers 45 and the surface L.

In manually slipping the pre-form B-l over the open end E of the peripherally closed housing 10, advantage is taken of the vertically and/or horizontally extending space S between the right hand end E of the housing and the left hand end 80 of the supporting surface 46 (FIG. 1). The leading edge 81 of the pre-form B-l is drawn manually through said space S with the pre-form opened up while being slipped overthe right hand end E of said housing 10, all as viewed in FIG. 1., In the fully slipped-on position of the pre-form B-l, the leading edge 81 thereof is substantially in the vertical plane of the rear edge of the upper flange 35.

After the pre-form B-l has been positioned in place as shown in full lines in FIG. 1, the pusher plate P is next advanced by operation of the air cylinder 40, and the pre-form B-l with the stack enclosed therein is thereby advanced out'of the housing 10 and then onto the supporting surface.46.into the position shown in dotted lines in FIG. 1 beneath the compaction press 60 and the shrink ring 61. In this position the open end 52 of the shipping pre-form B-lhas received and now encircles the pusher plate P. The open end 52 is kept from collapsing by the support it receives from the upper flange 34 in combination with the lower flange 32.

In the next. step, the pusher plate P is withdrawn to its initial full line position, as shown at the left in FIG. 1, leaving the pre-form B-l with its load of bags supported entirely by the surface L, or 46, in a position below the compaction press 60. Such withdrawal is effected by the operation of the air cylinder 40 in the reverse direction. While the pre-form B-l with its stack 15 of grocery bags is in such unenclosed freelysupported position below thecornpaction press 60, and with the shipping pre-form B-l still open-ended at 52, the compaction press is operated to vertically compress the stack 15 of grocery bags. Such operation is accomplished by any suitable means acting through a plunger 62 and pedestal 63 and guided by vertical guide rods 64 and 65. i

The heated shrink ring 61 can be operated substantially simultaneously, or contemporaneously with the compaction press 60, or the shrink ring can perform its function after the stack 15 has been compacted and while it is still under the compacting force of the press 60. Best results are obtained if the stack 15 is first compressed and is still in a compressed state under the platen 66 of the press 60 when the heat of the heated shrinking ring is applied. I

The ring 61 is of a rectangular shape in plan and of somewhat greater length and width than the shipping bag when loaded so that the shrink ring can be lowered into a position surrounding the loaded shipping bag B on all four sides. The shrink ring 61 is also of larger dimensions than the platen 66 of the press 60 so as to be movable into a position surrounding the platen (FIG. 4), either in the same horizontal plane or above or below the plane of the platen.

The shrink ring 61 may be heated in any suitable fashion but for purposes of illustration, the ring 61 has an electrical resistance heating element 70, such as an infrared resistance wire coil, mounted in a ring 71 of convergent reflecting surfaces directing radiant heat inwardly against the shipping bag surrounded by such ring. The ring 71 is supported within an open rectangular arrangement of a channel iron 72 suspended from rods73, and capable of being lowered into the full line position for exercizing its compacting action or of a more or less oval ring of heat-shrunk film material formed about a contracted opening 81.

During the same application of the heated shrink ring to the loadedshipping bag B, the film at the other end of the bag, that is heat-sealed at 54, is also caused to shrink and to contract inwardly and therefore more closely, as-indicated at 94 in FIG. 4, against the adjacent end 95 'of the stack 15. Such shrinkage reduces any tendency of the stack 15 to expand or of the individual grocery bags in the stack to get out of place or shift their relative positions in the shipping bag B.

The heated shrink ring 61 may be moved up or down during the heat-shrinking so as to be in the same plane as the median horizontal plane of the loaded shipping container B or in a plane above or below that median plane. Depending upon the height of the shrink ring and its distance from the ends of the loaded shipping bag, and also depending upon the intensity of the infrared at the irradiated surfaces of the ends of the shipping bag, the bag ends can be shrunk to any desired degree up to the limits of shrinkage for the particular plastic film that is selected for making the shipping bag. It is usually sufficient to shrink the bag to such an extent as to cause the film to contract into firm engaging contact with the articles within the loaded bag so as to immobilize such articles with respect to each other and to the bag that encloses them.

After the shrinking operation and with the bag B in a heated condition and still under the compacting pressure of the platen 66, the bag B is subjected to a quick cooling step that is carried out in apparatus 96, such as shown more or less diagrammatically in FIG. 5.

Said cooling apparatus 96 comprises an open-top box-like container of a size such as to receive a heated bag B from the heat-shrinking station. One end of said apparatus 96 is open, as at 97, and the other end is provided with a blower or suction. fan 98 for circulating about the bag B air, or other gas, at or below ambient temperatures to rapidly cool said bag B and set, harden or otherwise rigidify the film forming said bag B.

Bags B can be placed manually in the cooling apparatus 96 and removed manually therefrom. By the use of the cooling apparatus cooling of the heat-shrunk loaded bags B can be carried out much more quickly, thereby speeding up the whole operation, but except for the time-saving feature the bags could be allowed to cool in the atmosphere with nearly the same results. The cooling tends to set the plastic film of the bags into its heat-shrunk state in firmly engaging contact with the surfaces of the articles that are contiguous to the film as a result of the heat-shrinking operation.

Another result of the heat-shrinking operation is its rigidifying of the loaded bags so that each loaded bag can be handled as a relatively rigid unit for palletizing without fear of the articles therein becoming displaced from one another. FIG. 6 illustrates a loaded bag in its final state ready for palletizing if desired.

As indicated in FIG. 6, the plastic film 80 about the opening 81 in the end of the bag B may be in a more or less wrinkled and/or thickened state as a result of the heat-shrinking step. In that case, the thickened film 80 provides a strong edge about the opening 80 for manual gripping purposes in handling the loaded bag.

I claim: I

1. Apparatus for packaging articles, which comprises means for peripherally confining a bundle of said articles while leaving surface portions of said articles accessibly exposed, means for enveloping said bundle within an open-ended sleeve of a heat-shrinkable film, means for moving the enveloped bundle to a pressure station, means at said pressure station for effecting pressure contact between said enveloping means and said exposed surface portions and means for heatshrinking said film into close contact with said exposed article surface portions while leaving film edges surrounding said opening accessible for manual engagement after said heat-shrinking step has been performed.

2. Apparatus as defined by claim 1, wherein said articles are collapsible bags maintained in a stack by said confining means with surface portions of the ends of said stack left accessibly exposed.

3. Apparatus as defined by claim 2, wherein said confining means comprises a hinged set of panels for wrapping contact with the peripheral surfaces of said stack.

4. Apparatus as defined by claim 3, wherein an end pusher means engages one end of said stack' while the latter is within said confining means and serves to push said stack endwise out of said confining means.

5. Apparatus as defined by claim 4, wherein said pusher means has upper and lower flanges for engagement with the upper and lower surfaces of said one end of said stack.

6. Apparatus as defined by claim 5, wherein said confining means is stationary as a unit and said pusher means fits within said confining means with sufficient clearance to allow relative movement therebetween.

7. Apparatus as defined by claim 6, wherein said pusher means includes a generally rectangular plate having a plurality of openings.

8. Apparatus as defined by claim 7, wherein means are provided for causing a compressed gas to move said pusher means to advance a stack.

9. Apparatus as defined by claim 8, wherein tracks extend from said pusher means for providing a support for said stack while being advanced into a shipping container.

10. Apparatus as defined by claim 8, including heatenergized film shrinking means for application against an end of one of said shipping container after being filled to shrink the film thereof into firm contact with portions of the surface of articles within said container and contiguous to said film. g

1 1. In apparatus for loading a stack of smaller satchel or SOS type bags into a larger shipping container formed of a heat-shrinkable film, means comprising hingedly connected rectangular panels adapted to form an open-ended, bag-receiving, peripherally-confining, stationary housing, a relatively rigid pusher plate movable with clearance within said housing, a source of a fluid under pressure for energizing said pusher plate to advance a stack of said bags through and out of said housing, and means for heat-shrinking and compressing said stack after loading the same into a shipping container, means for cooling said heat-shrunk stack and means for maintaining said stack within said shipping container in a compacted state.

12. Apparatus as defined by claim 11 including a heat energized device for heat-shrinking localized portions of said heat-shrinkable film into contact engagement with surface portions of said stack.

13. The apparatus defined by claim 12, wherein said fluid is air and said device is electrically heated and is adapted to direct heat to localized portions of said shipping container after being loaded.

14. Apparatus as defined by claim 12, including means in said housing providing tracks 'of reduced frictionfor supporting the stacks as they are moved relative to said housing.

15. Apparatus as defined by claim 14, wherein said track-providing means are a plurality of fingers secured to the lower of said flanges and extending over the corresponding lower one of said panels.

16. Apparatus as defined by claim 15, wherein said fingers extend beyond the open end of said housing when said pusher plate is in its farthest advanced position. 

1. Apparatus for packaging articles, which comprises means for peripherally confining a bundle of said articles while leaving surface portions of said articles accessibly exposed, means for enveloping said bundle within an open-ended sleeve of a heatshrinkable film, means for moving the enveloped bundle to a pressure station, means at said pressure station for effecting pressure contact between said enveloping means and said exposed surface portions and means for heat-shrinking said film into close contact with said exposed article surface portions while leaving film edges surrounding said opening accessible for manual engagement after said heat-shrinking step has been performed.
 2. Apparatus as defined by claim 1, wherein said articles are collapsible bags maintained in a stack by said confining means with surface portions of the ends of said stack left accessibly exposed.
 3. Apparatus as defined by claim 2, wherein said confining means comprises a hinged set of panels for wrapping contact with the peripheral surfaces of said stack.
 4. Apparatus as defined by claim 3, wherein an end pusher means engages one end of said stack while the latter is within said confining means and serves to push said stack endwise out of said confining means.
 5. Apparatus as defined by claim 4, wherein said pusher means has upper and lower flanges for engagement with the upper and lower surfaces of said one end of said stack.
 6. Apparatus as defined by claim 5, wherein said confining means is stationary as a unit and said pusher means fits within said confining means with sufficient clearance to allow relative movement therebetween.
 7. Apparatus as defined by claim 6, wherein said pusher means includes a generally rectangular plate having a plurality of openings.
 8. Apparatus as defined by claim 7, wherein means are provided for causing a compressed gas to move said pusher means to advance a stack.
 9. Apparatus as defined by claim 8, wherein tracks extend from said pusher means for providing a support for said stack while being advanced into a shipping container.
 10. Apparatus as defined by claim 8, including heat-energized film shrinking means for application against an end of one of said shipping container after being filled to shrink the film thereof into firm contact with portions of the surface of articles within said container and contiguous to said film.
 11. In apparatus for loading a stack of smaller satchel or SOS type bags into a larger shipping container formed of a heat-shrinkable film, means comprising hingedly connected rectangular panels adapted to form an open-ended, bag-receiving, peripherally-confining, stationary housing, a relatively rigid pusher plate movable with clearance within said housing, a source of a fluid under pressure for energizing said pusher plate to advance a stack of said bags through and out of said housing, and means for heat-shrinking and compressing said stack after loading the same into a shipping container, means for cooling said heat-shrunk stack and means for maintaining said stack within said shipping container in a compacted state.
 12. Apparatus as defined by claim 11 including a heat energized device for heat-shrinking localized portions of said heat-shrinkable film into contact engagement with surface portions of said stack.
 13. The apparatus defined by claim 12, wherein said fluid is air and said device is electrically heated and is adapted to direct heat to localized portions of said shipping container after being loaded.
 14. Apparatus as defined by claim 12, including means in said housing providing tracks of reduced friction for supporting the stacks as they are moved relative to said housing.
 15. Apparatus as defined by claim 14, wherein said track-providing means are a plurality of fingers secured to the lower of said flanges and extending over the corresponding lower one of said panels.
 16. Apparatus as defined by claim 15, wherein said fingers extend beyond the open end of said housing when said pusher plate is in its farthest advanced position. 